Scaffold



April 26, 1949. A. w. DU FERRET S CAFFOLD Filed April 25, 1946 IN V ENTOR ARTHUR W DURE'RRET kxzi wg ATTORNEY Patented Apr. 26, 1949 PAT 'EN TF Fl CE 'S'CAFFOLD Arthur W. Z'Dn :Pierret, St. Louis, Mo., assignor toAutomatic Devices, Incorporated, St. Louis, Mo.,

ame ioration of Missouri Application April 25, 1946, Serial No. 664,850

Slaims. 1

.iBhi-s invention :relates to scaffolds and more nanticularlyito :animproved lportable scaffold and bracing structure "therefor.

Onezofxthexobjects of myeinvention is to produce animprovedport'able'scaffold that can be quickly erected and taken "d0Wn-'and yetwill be strong and rigid.

.Another ebject is to-produce a portable scaffold in which the bracingmembers thereof can 'be quickly changed f'rom :one position to anotherto permit the'scafiold to be=used invarious places,

particularly where there may be obstructions.

Still another object is 'to produce an improved removable br-aoeconstruction "for a sc'aiiold.

-A further'object is'to produce a scaffold which I erected in a rigidmanner to produce a scaffold 5 of any desired height -'or length.

Otherobjects-o'f my invention will become apparent "from the followingdescription taken in connection with the "accompanying drawings inwhich:

Figure 1 is *aperspec'tive' view of a single unit scaffold embodying myinvention;

"-Figure-2 is-e longitudinal section view showing azpreferre'd j'ointconstruction whereby the height of the posts m-ay be increased;

Figure *3 is :an-erilarged side view showing one end of a bracestructure and the manner "it is attached ts -a -post;

Figure 4 *is =a-sectional view taken on the "line 1-4 of Figure B; and

Figure b is a'secti'onall view showin the manner in '-whi'cha'-plurality of braces can be attached to a:single post when it 'isdesired'to have removable end frame brace structure and also a scaffoldembodying several units.

Referring to the drawings in detail and first to Figures'slto 4,inclusive,- the scaffold unit shown asvem'bodying-my invention has twoend frames El and .2 0f .like construction. Each of these end frameshastwo posts 3 and-:4 which are shown as being tubular. The posts 3 :and"4 of each end \framehave their'upper ends connected by a horizontalcrossbar 5 welded to the posts some distanceifrom theupper end. In orderto make this cross rbarzmore rigid, angular braces 6 and Textendbetweenthesposts and the crossbar 5 inthe manner shown. These braces mayhave any desired "cross sectional shape and one end of each 'sbracetiswelded to aapost and the other end to orossban'a'tas'point'spacedlinwardly from the braces 9 and it] each have "their endswelded itcthe post and .the cross bar as shown. The end frames, as thusaconstructed, :are very rigid.

In order :.to complete the scaffold unit structure a plurality ofstringers S :are employed to Join the end frames in spaced apart:relation. :Each ofthese :stringers is of like construction :and each isarranged to have its ends connected to anlend trame by iremovab'le.means .so that the scaffold can "be erecteduand taken down as .desired.

:Each stringer S is formed with za cross bar 1H which maybe of anydesired .cross section and of a length corresponding to the spacingdesired between the end frames. As shown, this :cross bar l! is oftubular construction. The ends of the crossbar have secured theretomembers 21:2 and ['3 of considerable length. These members are shownas'hav'ing a curved cross section and are arranged to*be at right anglesto the-axis of the cross bar 1 I with the "joints between the members l2and i3 and the cross bar being adjacent the upper ends of the members.Between the member 12 and the cross bar is an angular brace t andbetween the member E3 and the crossbar is an angular brace l'5.'Thebraces are permanently-secured to the cross bar and the members asby welding and maybe of any desired cross sectional shape. With'thestringers S constructed as shown, they are arranged to be attached tothe posts of the end -frames by means of suitable removable means suchas bolts 16 having wing nuts '17, which bolts extend through holes T8 inthe end posts.

The two'posts 4 of the two end-framesarenonnected adjacent their tops bya stringer Sand adjacent their bottoms by another stringer S. Similarly-'st1-ingers S connect the posts 3 of the end frames 'a'djacer'it theirtops andbottoms. Cit is tobenotedthatthe curved members i 2=-and 13, atthe endsof each cross .bar .11 of 'the'stringers, have their innercylindrical surfaces facing outwardly from the end of thecross bar andwhen the cross baris attached to the end posts theend posts will bereceived in the recesses oi-the members l2 and 13 as best illustratedin'Figure-4. In "order that there will be a tight connectionibetween theend' posts and themembers l2-and 43 at the-ends of the stringerswhenever the bol-ts'fl fi are tightened up, the radius-of curvature -ofthe inner surface of the member l2 is'slightly'smaller than theradius ofcurvature of the surface-o'f the tubular members forming theposts.-".Phus when the bolts are drawn up tight the surface of the post willhave wedging in the members l2 or [3 with an accompanyin spreadingaction and there will be produced a clamping action which will result ina rigid and tight connection. The relationship between the radius ofcurvature of one of the members, such as l2, and the radius of curvatureand the surface of the post with which it cooperates is illustrated inFigure 4.

In order to provide a platform for the scaffold, planks P may be laidacross the upper cross bars 5 of the two end frames. These planks canhave angle cleats 58 so as to prevent them from shift-- ing on the crossbars. If it is desired to have the scaffold easily movable about as, forexample, when used for interior work, the bottoms of the end posts ofboth end frames can be provided with casters is.

Under certain conditions it may be desirable to increase the height ofthe scaffold unit which has just been described, and to accomplish thisthe upper ends of the end posts which project above the cross bars 5have welded thereto sleeves of an internal diameter to fit over the endsof the posts. which can be slipped tubular members 2i having the sameexternal diameter as the posts. The tubular members 2! to be associatedwith the end posts of each end frame are connected together by a crossbar 22 welded to the tubular members as shown. There is also providedwood cross members 23 which can be secured by bolts 2t to the tubularmembers. The cross bars 22 and the cross members 23 thus provide ahigher structure upon which a plank or planks, such as the plank 25, canbe placed. If it should be desired to put several scaffold units on topof the scaffold unit already described, these units will be constructedin the same manner as the single unit except that the casters areeliminated from the bottoms of the legs. Such a unit, or units, can thenbe set on top of the base unit by inserting the corner posts of the endframes in sockets provided by sleeves 20 at the tops of the end posts.

The scaffold just described can be used in almost any desired place andis adapted for many uses by merely changing the position of thestringers. If it should be desired to push the scaffold unit over anobject on the floor, the scaffold can be conditioned for this by havingits lower stringers S raised up to a height so that they will clear theobject. Such position of the two lower stringers is shown by the dottedlines in Figure 1. Each post is provided with bolt holes is inlongitudinally spaced relation on the end post to permit this shiftingof the lower stringers. If it is desired to lower the two top stringers,such can be quickly accomplished. If it is not desired to use the upperextension formed by the tubular members 2! and the cross pieces 22 andcross members 23 as, for example, in a room with a low ceiling, thenthese pieces can be quickly removed by lifting the tubular members outof the sockets provided by the sleeves Furthermore, if it should bedesired to lower the main platform, which is indicated by the planks P,this can be done by taking the wood cross members 23 and bolting them onthe end frames below the cross bars 5, using the holes is for receivingthe bolts 24. Such a positioning of the wood cross bars 23 is shown indotted lines in Figure 1. The planks P will then be placed upon thesecross bars 23.

If it should be desired to have the cross members '5 and 8 for the endframes removable in- These sleeves provide sockets into stead ofpermanently secured to the posts 3 and 4, as shown in Figure 1, endconstructions similar to the end constructions of the stringers S can beemployed on the cross bars 5 and 8 and then cross bars attached by meansof bolts. Such an arrangement is illustrated in Figure 5 wherein, inaddition to the stringer S attached to an end post 2t, there is provideda stringer S which is a removable stringer for connecting the two postsof the end frame together, it being understood that there is anotherpost similar to the post 26 which, together with the stringer S, formspart of the end frame. The stringer S has its end constructed in thesame manner as the stringer S illustrated in Figure 3 and a bolt 21 andWing nut 28 are provided for securing the end of this stringer to thepost.

If it should be desired to add additional sections on the scaffolds tolengthen it, then this can be accomplished by merely connectingadditional stringers to the end posts as also illustrated in Figure 5.For example, the stringer S can be secured to the opposite side of thepost 26 from the end of stringer S. The same bolt I6 can be employed toconnect the stringers S and S to the post. With such an arrangement itis seen that the scaffold can be built of any desired length withadjacent sections having common end frames. The stringers S and Sbetween the end frames can be so attached to their posts as to be out ofline if desired. When several stringers are to be attached to a singlepost in a manner illustrated in Figure 5,, the curved members whichcooperate with the post have an arch which is slightly less than thequarter of a circle so there will be s-ufiicient room for all of thesemembers to fit around the post.

In the scaffold illustrated the post members are shown as being tubular,but it is to be understood that other cross sectional shapes can be usedand also other cross sectionalshapes for the end members l2 and 3 forthe stringers can be used to cooperate with these posts to obtain a fitwhen the stringers are bolted thereto. For example. the posts may have asquare cross section and the shape of the members l2 and I3 may beangular so that the one corner of the post will be received in theangular portion of the members l2 or it. The angle of the members I2 andis should be slightly less than degrees so as to obtain the sameclamping action as is obtained by the difference of radius in curvatureof the round posts and the end members l2 or it as illustrated in Figure4. Therefore, being awar of the possibility of modification in theparticular structure shown and described, without departing from thefundamental principles of my invention, I do not intend that the scopeof the invention be limited in any manner except in accordance with theappended claims.

What is claimed is:

1. In a scaffold unit, a pair of end frames each of which comprises apair of posts and bracing between the posts including platformsupporting and means for joining the end frames together comprisingupper and lower stringers connecting each post of one end frame with apost of the other end frame, each of said Stringers including a bar, anelongated member permanently secured to each end of the .bar andprovided with a longitudinal exposed grOOVe having its axis at rightangles to the longitudinal axis of the bar, removable means for clampingthe elongated member to a post with the post received in thelongitudinal groove, each groove and post having such cooperatingrelationship and the clamping means being so associated with the postand member that said clamping means can cause the post to wedge into thegroove with a spreading action thereon, and means comprising spacedholes in the post for cooperation with the removable clamping means forpermitting the elongated members of at least two of the stringers to beattached to their posts at diiferent points on the posts.

2. A detachable stringer for connecting and bracing spaced round postsof a scaffold, said stringer comprising a bar, an elongated memberpermanently secured to each end of the bar and having a curved surfacethe axis of which extends longitudinally of the member and at rightangles to the longitudinal axis of the bar and the radius of curvatureof which is slightly less than the radius of curvature of the surface ofthe end post, and means for associating detachable connecting means witheach longitudinal member to thereby clamp the elongated member to a postwith the curved surfaces adjacent the post surface, said detachablemeans when producing a clamping action causing the elongated members toyield in a manner to increase the radius of curvature of the curvedsurface.

3. A detachable stringer for connecting and bracing spaced round postsof a scaifold, said stringer comprising a bar, an elongated memberpermanently secured to each end of the bar and having a curved surfacethe axis of which extends longitudinally of the member and at rightangles to the longitudinal axis of the bar and the radius of curvatureof which is slightly less than the radius of curvature of the surface ofthe end post, a brace element between each elongated member and the rodwith its ends permanently secured to the member and red at points spacedfrom the connecting point of the rod and member, and means forassociating detachable connecting means with each longitudinal member tothereby clamp the elongated memher to a post with the curved surfacesadjacent the post surface.

4. A detachable stringer for connecting and bracing spaced posts of ascaffold, said stringer comprising a bar, an elongated memberpermanently secured to each end of the bar and having an outwardlyfacing roove the axis of which extends longitudinally of the member andat right angles to the longitudinal axis of the bar, said groove havinga surface contour similar to the post surface with which it is tocooperate but being of such less cross width than the post atcorresponding points that when clamped to the post the post will have aspreading action on the side walls thereof, and means for associatingconnecting means with the elongated member for clamping it to a post andto cause a spreading action to occur.

5. A detachable joint structure for connecting a scaffold stringer to ascaifold post, said joint comprising an elongated member welded to thebar at one end thereof and provided with an exposed longitudinal grooveat right angles to the axis of the stringer, said roove having such awidth between the outer edges of its walls that said edges will engagethe post surface without the bottom of the groove engaging the postsurface, and bolt means extending through the elongated member and thepost for clamping the member to the post and causing the post to apply aspreading force to the opposed walls of the groove.

ARTHUR W. DU FERRET.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,828,487 Booser Oct. 20, 19311,920,130 Pease et al July 25, 1933 2,126,720 Beatty et al Aug. 16, 19382,303,428 Black Dec. 1, 1942 2,305,563 Uecker et a1 Dec. 15, 19422,308,831 Roney et al Jan. 19, 1943 2,311,988 Lavin Feb. 23, 19432,361,614 Dugan et al. Oct. 31, 1944 2,363,382 Attwood Nov. 21, 19442,406,078 Hushower Aug. 20, 1946 v FOREIGN PATENTS Number Country Date507,454 Germany Sept. 22, 1930

